int editDistance(string s1, string s2){
    int m = s1.length();
    int n = s2.length();
    int dp[m+1][n+1];
    for (int i = 0; i <= m; i++) {
        dp[i][0] = i;
    }
    for (int j = 0; j <= n; j++) {
        dp[0][j] = j;
    }

    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
        if (s1[i-1] == s2[j-1]) dp[i][j] = dp[i-1][j-1];
            else dp[i][j] = 1 + min(min(dp[i][j-1],dp[i-1][j]),dp[i-1][j-1]);
        }
    }
    return dp[m][n];
}
